U.S. Pat. No. 4,878,815 dated Nov. 7, 1989 shows a high pressure reciprocating pump utilizing high pressure water jet cleaning for producing fluid pressure up to 35,000 psi. When higher pressures are encountered, such as pressures in the range of 50,000 psi to 60,000 psi, stress concentrations at such high fluid pressure result in undue wear and cracks, particularly adjacent the entrances to discharge flow holes or openings through which the high pressure fluid is discharged on the power stroke. Stress concentrations are high at the comers of the openings and hard alloy materials for such areas are expensive and difficult to machine or round at the comers where the stress concentrations occur. Particularly where small diameter openings are provided for very high fluid pressures, the corners or entrances to such small diameter openings are difficult for machine or chamfer.
As shown in the '815 patent, the plunger in the suction stroke results in opening of the suction valve to permit fluid within the pump chamber. Then, during the following power stroke, the high fluid pressure is discharged from the pump chamber through a plurality of relatively small discharge holes or openings into a large discharge port. The corners of the entrances to the plurality of relatively small discharge openings are subjected to stress concentrations from the high fluid pressure during the power stroke which results in wear and some cracks at very high pressures encountered.
An object of the invention is to provide a high pressure reciprocating pump for high fluid pressures between 30,000 and 60,000 psi in which high stress concentrations are minimized.
Another object of the invention is to provide such a high pressure reciprocating pump in which a replaceable valve cartridge is utilized.